Re: [PATCH 23/47] target-info: add target_config_multiprocess

[Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>]

On 8/31/2026 7:48 AM, Philippe Mathieu-Daudé wrote:
> On 2026-08-29 0:58, Pierrick Bouvier wrote:
>> For some devices/machines, we'll need to access target configuration,
>> but without relying to target headers. Thus, we add the needed
>> information in target-info.
>>
>> Signed-off-by: Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>
>> ---
>>   include/qemu/target-info-impl.h | 3 +++
>>   include/qemu/target-info.h      | 7 +++++++
>>   meson.build                     | 1 +
>>   target-info-def.c               | 7 +++++++
>>   target-info.c                   | 5 +++++
>>   5 files changed, 23 insertions(+)
>>
>> diff --git a/include/qemu/target-info-impl.h b/include/qemu/target-
>> info-impl.h
>> index cf42aabbc8b..dbd7a5a2071 100644
>> --- a/include/qemu/target-info-impl.h
>> +++ b/include/qemu/target-info-impl.h
>> @@ -30,6 +30,9 @@ typedef struct TargetInfo {
>>       unsigned page_bits_init;
>>       /* runtime equivalent of TARGET_PAGE_BITS_VARY definition */
>>       bool page_bits_vary;
>> +
>> +    /* CONFIG_MULTIPROCESS */
>> +    bool config_multiprocess;
>>   } TargetInfo;
>>     /**
>> diff --git a/include/qemu/target-info.h b/include/qemu/target-info.h
>> index b23e5bc5865..579c43332fb 100644
>> --- a/include/qemu/target-info.h
>> +++ b/include/qemu/target-info.h
>> @@ -42,6 +42,13 @@ const char *target_cpu_type(void);
>>    */
>>   bool target_big_endian(void);
>>   +/**
>> + * target_config_multiprocess:
>> + *
>> + * Returns true if target defines CONFIG_MULTIPROCESS.
>> + */
>> +bool target_config_multiprocess(void);
>> +
>>   /**
>>    * target_base_arm:
>>    *
>> diff --git a/meson.build b/meson.build
>> index 5da6c15551e..8023da4a147 100644
>> --- a/meson.build
>> +++ b/meson.build
>> @@ -4259,6 +4259,7 @@ foreach target : target_dirs
>>     arch_deps = []
>>     c_args = ['-DCOMPILING_PER_TARGET',
>>               '-DCONFIG_TARGET="@0@-config-target.h"'.format(target),
>> +            '-DCONFIG_DEVICES="@0@-config-devices.h"'.format(target),
>>     ]
>>     link_args = emulator_link_args
>>   diff --git a/target-info-def.c b/target-info-def.c
>> index d121b8c0170..9d51371f766 100644
>> --- a/target-info-def.c
>> +++ b/target-info-def.c
>> @@ -15,6 +15,10 @@
>>   #include "exec/cpu-defs.h"
>>   #include "exec/page-vary.h"
>>   +#ifndef CONFIG_USER_ONLY
>> +#include CONFIG_DEVICES
>> +#endif
>> +
>>   /* Validate correct placement of CPUArchState. */
>>   QEMU_BUILD_BUG_ON(offsetof(ArchCPU, parent_obj) != 0);
>>   QEMU_BUILD_BUG_ON(offsetof(ArchCPU, env) != sizeof(CPUState));
>> @@ -39,6 +43,9 @@ static const TargetInfo target_info_stub = {
>>       .page_bits_vary = false,
>>       .page_bits_init = TARGET_PAGE_BITS,
>>   #endif
>> +#ifdef CONFIG_MULTIPROCESS
>> +    .config_multiprocess = true,
>> +#endif
>>   };
>>     target_info_init(target_info_stub)
>> diff --git a/target-info.c b/target-info.c
>> index 012b384036d..5db2a6049ac 100644
>> --- a/target-info.c
>> +++ b/target-info.c
>> @@ -42,6 +42,11 @@ bool target_big_endian(void)
>>       return target_endian_mode() == ENDIAN_MODE_BIG;
>>   }
>>   +bool target_config_multiprocess(void)
>> +{
>> +    return target_info()->config_multiprocess;
>> +}
>> +
>>   bool target_base_arm(void)
>>   {
>>       switch (target_arch()) {
> 
> To avoid TargetInfo::config_multiprocess we can use:
> 
> -- >8 --
> diff --git a/include/hw/remote/mpqemu-link.h b/include/hw/remote/mpqemu-
> link.h
> index 4ec0915885..2dee94ac64 100644
> --- a/include/hw/remote/mpqemu-link.h
> +++ b/include/hw/remote/mpqemu-link.h
> @@ -98,2 +98,7 @@ bool mpqemu_msg_valid(MPQemuMsg *msg);
> 
> +static inline bool target_config_multiprocess(void)
> +{
> +    return IS_ENABLED(CONFIG_MULTIPROCESS_ALLOWED);
> +}
> +

We need to store the value of CONFIG_MULTIPROCESS somewhere per target,
so it can't be a common function.
Also, I tried using IS_ENABLED in target-info structure instead of
ifdef, but for some reason, it always returned false. Also, its
implementation is far from being easy to read.

>  #endif
> ---
> 
> 

Regards,
Pierrick